Metal ingots, billets and other castparts may be formed by a casting process which utilizes a vertically oriented mold situated above a large casting pit beneath the floor level of the metal casting facility, although this invention may also be utilized in horizontal molds. The lower component of the vertical casting mold is a starting block. When the casting process begins, the starting blocks are in their upward-most position and in the molds. As molten metal is poured into the mold bore or cavity and cooled (typically by water), the starting block is slowly lowered at a pre-determined rate by a hydraulic cylinder or other device. As the starting block is lowered, solidified metal or aluminum emerges from the bottom of the mold and ingots, rounds or billets of various geometries are formed, which may also be referred to herein as castparts.
While the invention applies to the casting of metals in general, including without limitation, aluminum, brass, lead, zinc, magnesium, copper, steel, etc., the examples given and preferred embodiment disclosed may be directed to aluminum, and therefore the term aluminum or molten metal may be used throughout for consistency even though the invention applies more generally to metals.
While there are numerous ways to achieve and configure a vertical casting arrangement, FIG. 1 illustrates one example. In FIG. 1, the vertical casting of aluminum generally occurs beneath the elevation level of the factory floor in a casting pit. Directly beneath the casting pit floor 101a is a caisson 103, in which the hydraulic cylinder barrel 102 for the hydraulic cylinder is placed.
As shown in FIG. 1, the components of the lower portion of a typical vertical aluminum casting apparatus, shown within a casting pit 101 and a caisson 103, are a hydraulic cylinder barrel 102, a ram 106, a mounting base housing 105, a platen 107 and a bottom block 108 (also referred to as a starting head or starting block base), all shown at elevations below the casting facility floor 104.
The mounting base housing 105 is mounted to the floor 101a of the casting pit 101, below which is the caisson 103. The caisson 103 is defined by its side walls 103b and its floor 103a. 
A typical mold table assembly 110 is also shown in FIG. 1, which can be tilted as shown by hydraulic cylinder 111 pushing mold table tilt arm 110a such that it pivots about point 112 and thereby raises and rotates the main casting frame assembly, as shown in FIG. 1. There are also mold table carriages which allow the mold table assemblies to be moved to and from the casting position above the casting pit.
FIG. 1 further shows the platen 107 and starting block base 108 partially descended into the casting pit 101 with castpart 113 (which may be an ingot or a billet being partially formed. Castpart 113 is on the starting block base 108, which may include a starting head, or bottom block, which usually (but not always) sits on the starting block base 108, all of which is known in the art and need not therefore be shown or described in greater detail. While the term starting block is used for item 108, it should be noted that the terms bottom block and starting head are also used in the industry to refer to item 108, bottom block is typically used when an ingot is being cast and starting head when a billet is being cast.
While the starting block base 108 in FIG. 1 only shows one starting block 108 and pedestal, there are typically several of each mounted on each starting block base, which simultaneously cast billets, special tapers or configurations, or ingots as the starting block is lowered during the casting process.
When hydraulic fluid is introduced into the hydraulic cylinder at sufficient pressure, the ram 106, and consequently the starting block 108, are raised to the desired elevation start level for the casting process, which is when the starting blocks are within the mold table assembly 110.
The lowering of the starting block 108 is accomplished by metering the hydraulic fluid from the cylinder at a pre-determined rate, thereby lowering the ram 106 and consequently the starting block at a pre-determined and controlled rate. The mold is controllably cooled during the process to assist in the solidification of the emerging ingots or billets, typically using water cooling means.
There are numerous mold and casting technologies that fit into mold tables, and no one in particular is required to practice the various embodiments of this invention, since they are known by those of ordinary skill in the art.
The upper side of the typical mold table operatively connects to, or interacts with, the metal distribution system. The typical mold table also operatively connects to the molds which it houses.
When metal is cast using a continuous cast vertical mold, the molten metal is cooled in the mold and continuously emerges from the lower end of the mold as the starting block base is lowered. The emerging billet, ingot or other configuration is intended to be sufficiently solidified such that it maintains its desired profile, taper or other desired configuration. There is an air gap between the emerging solidified metal and the permeable ring wall. Below that, there is also a mold air cavity between the emerging solidified metal and the lower portion of the mold and related equipment.
Once casting is complete, the castpart, an ingot in this example, is removed from the bottom block. FIG. 1A illustrates an exemplary bottom block configuration with a castpart 113 being removed from the bottom block 108 after casting. FIG. 1A illustrates a bottom block 108 with a particular shape or configuration in the internal cavity which receives the initial flow of molten metal during the casting process, and the outer perimeter of the castpart 113 once solidified takes that shape.
FIG. 1A illustrates sloped portions 115 & 116, and indented portion 119 on castpart 113. Sloped portions 115 & 116 generally correspond to bottom block indentations 117 & 114 in shape and configuration, and with some variance generally related to shrinkage or other casting factors. Bottom block protrusion 118 corresponds in shape and configuration to Castparts indentation 119, all as can be seen in FIG. 1A. The sloped portions 115 & 116 in prior art ingots have been different angles, such as thirty degrees, forty-five degrees, and sixty degrees.
FIG. 1B is an elevation cross sectional view of a prior art mold wall 142 with casting surface 142a, castpart 141, mold framework 143, coolant chamber 149, coolant impact zone 146 where the coolant (typically water) hits and cools the castpart 141. Embodiments of this invention may be applied to prior art of all types, including the mold configuration illustrated in FIG. 1B.
In conventional casting and direct chill casting processes for rolling ingot, an ingot goes through a substantial transformation process during rolling. Ingot may be rolled into plate, can stock, aluminum foil and other products of differing dimensions and thicknesses by a process which sends the ingot through a series of rollers repetitively, with the rollers being sequentially moved closer together. This rolling equipment may be referred to as a rolling stand.
One of the problems associated with this process is that a portion of the rolling ingot is wasted due to a phenomenon sometimes referred to as alligatoring. Alligatoring occurs during the rolling process when metal from the main body of the ingot gets rolled and pushed over the end of the ingot on the head and the butt sides. When the ingot is observed in this condition from the side view the head and the butt resemble the mouth of an alligator, which is where the term alligatoring originated. Alligatoring is illustrated in FIG. 9. During the rolling process, the ends of the ingots which exhibit alligatoring are cut off, thereby resulting in a substantial amount of waste of aluminum which must be reheated and re-cast, in addition to the expense of doing so.
In some prior art, it has been shown that by producing an angle with a tapered head and butt, alligatoring may be reduced or eliminated.
It is an object of some embodiments of this invention to provide an automated variable dimensioned mold casting and bottom block system which provides tapered and other configurations of castparts.
It is an object of some embodiments of this invention to provide an automated variable dimensioned mold casting system which reduces end crop losses.
Other objects, features, and advantages of this invention will appear from the specification, claims, and accompanying drawings which form a part hereof. In carrying out the objects of this invention, it is to be understood that its essential features are susceptible to change in design and structural arrangement, with only one practical, and preferred embodiment being illustrated in the accompanying drawings, as required.